T40G defaults to ntp time?

[Retcheverry]

Hello all,

I've been configuring a PoC with Yealink T40g's.
One of the things I've been noticing is that the latest 3cx approved firmware: 76 83 0 55 has the DHCP time option set to no and tries to get its time from cn.pool.ntp.org
That's fine and dandy on an open network but this implementation has all the IP phones on their own subnet and only able to talk to the VoIP server and themselves.
These are the first 5 phones I'm using for a PoC, but the final setup will have between 50 and 100 phones.
My point is: ¿Why is the DHCP option OFF by default? That makes it so much harder to auto-provision. If the time cannot be set because the phone ignores DHCP options for time server then the auto-config fails due to the https cert not being yet valid!

This only has 3 solutions in my opinion:
1. Set each and every phone to DHCP time = yes (adding a lot of overhead to an otherwise automatic procedure)
2. Allow the phones to get to the internet (this is frowned upon in this company)
3. Change the default on the firmware, but there might be a reason why the engineers decided to set it to no?

I've currently done a very ugly workaround in that the phones are allowed to only connect to cn pool net org

What would be the recommended solution?

BTW Akismet is blocking my post, had to edit several times, why?